Hydrogen storage on microporous zeolites was examined using a high pressure dose of hydrogen at 30 C. The roles of the framework structure, surface area, and pore volume of the zeolites on hydrogen adsorption were investigated. The largest hydrogen storage was obtained on the ultra stable Y (USY) zeolite (0.4 wt%). The hydrogen adsorption isotherms on the zeolites reached a maximum after a hydrogen pressure of 50 bar. The amount of hydrogen adsorption on Mordenite (MOR) zeolites increased with increasing Si/Al molar ratio, which was achieved by dealumination. The amount of hydrogen adsorption increased linearly with increasing pore volume of the zeolites. The hydrogen adsorption behavior was found to be dependent mainly on the pore volume of the zeolites. (C) 2010 Elsevier Ltd. All rights reserved.